Fungal diseases in fruit crops compromise productivity even when synthetic fungicides are applied. However, growing health and environmental concerns have made such products less attractive to consumers. In this context, the present study aimed to extract and characterise the essential oil (EO) from leaves and flowers of African basil (Ocimum gratissimum L.) by hydrodistillation and to evaluate its bioactivity against the fungi Botrytis cinerea, Fusarium guttiforme and Colletotrichum musae. Average EO yields were 3.90% w/w (leaves) and 2.60% w/w (flowers). Chromatographic analysis identified four constituents, mainly mono- and sesquiterpenes, with eugenol as the major compound (> 80%). Both the EO and pure eugenol displayed fungicidal activity against F. guttiforme and C. musae at 0.50 and 0.80 µL mL⁻¹ (EO) and at 0.50 and 1.20 µL mL⁻¹ (eugenol), respectively. The EO and eugenol were fungistatic against B. cinerea in vitro. The EO also inhibited more than 95% of C. musae conidial germination from 0.20 µL mL⁻¹. In vivo assays, the EO reduced anthracnose severity in bananas. Molecular docking studies revealed that germacrene D and (E)-caryophyllene exhibited the strongest binding affinities to the fungal CYP51 enzyme, with binding energies of - 7.6 and - 7.3 kcal/mol, respectively, indicating their potential as effective antifungal agents. These findings indicate that African basil EO is a promising biofungicide and could be strategically integrated into sustainable crop protection programmes.
Júlio et al. (Wed,) studied this question.